Lfp as initiator of in-battery polymerization of conducting polymers for high-rate-charging cathodes

ABSTRACT

Cathodes for a fast charging lithium ion battery, processes for manufacturing thereof and corresponding batteries are provided. Cathode formulations comprise spinel and/or layered structure cathode material with 5-10% of cathode material having an olivine-based structure as polymerization initiator, binder material, and monomer and/or oligomer material selected to polymerize into a conductive polymer upon partial delithiation of the olivine-based structure cathode material during at least a first charging cycle of a cell having a cathode made of the cathode formulation. When the cathode is used in a battery, polymerization is induced in-situ (in-cell) during first charging cycle(s) of the battery to provide a polymer matrix which is evenly dispersed throughout the cathode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-part of U.S. application Ser. No.15/686,788, filed on Aug. 25, 2017, which is a continuation of U.S.application Ser. No. 15/434,083, filed on Feb. 16, 2017, which claimsthe benefit of U.S. Provisional Patent Application No. 62/432,588, filedDec. 11, 2016, all of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION 1. Technical Field

The present invention relates to the field of batteries, and moreparticularly, to cathodes for fast charge lithium ion batteries.

2. Discussion of Related Art

Rechargeable lithium batteries are extensively used for portableelectronic devices as well as hybrid electronic vehicles. The cellcapacity and rate capability as well as safety, environmentalcompatibility, life cycle, and cost are among the commercialconsiderations in preparing and using various types of batteries. Theolivine LiFePO₄ (LFP) cathode material is known to be low-cost, safe,environmentally benign, and further, provides beneficial cyclability andlarge capacity at high rates of charge and discharge. It is noted thatthe LFP particles used are of nano-scale and/or are coated with carbon;due to poor kinetic response of electronic and Lit-ion transfer underrapid-rate conditions.

SUMMARY OF THE INVENTION

The following is a simplified summary providing an initial understandingof the invention. The summary does not necessarily identify key elementsnor limit the scope of the invention, but merely serves as anintroduction to the following description.

One aspect of the present invention provides a cathode, prepared from acathode formulation comprising: cathode material having spinel orlayered structure, up to 10 wt % cathode material having anolivine-based structure, binder material, and monomer and/or oligomermaterial selected to polymerize into a conductive polymer upon partialdelithiation of the olivine-based structure cathode material during atleast a first charging cycle of a cell having the cathode, wherein: themonomer and/or oligomer material is in monomer and/or oligomer form inthe cathode in its pristine form prior to the first charging cycle ofthe cell, the partial delithiation is carried out electrochemicallyduring the first charging cycle of the cell, and following the firstcharging cycle of the cell, the monomer and/or oligomer material is atleast partly polymerized.

These, additional, and/or other aspects and/or advantages of the presentinvention are set forth in the detailed description which follows;possibly inferable from the detailed description; and/or learnable bypractice of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of embodiments of the invention and to showhow the same may be carried into effect, reference will now be made,purely by way of example, to the accompanying drawings in which likenumerals designate corresponding elements or sections throughout.

In the accompanying drawings:

FIGS. 1 and 7 are high level schematic illustrations of cathodeformulations, cathodes and cells, according to some embodiments of theinvention.

FIGS. 2A-2C illustrate examples for a prior art charging curve (FIG.2A), a first cycle of a charging curve of the pristine cell with thepristine cathode having pyrrole monomers as monomer and/or oligomermaterial (FIG. 2B), and a potential curve of the pristine cathode havingpyrrole monomers as monomer and/or oligomer material which is surfacepolymerized outside cell, as comparison (FIG. 2C), according to someembodiments of the invention.

FIG. 3 is an illustration of an experimental comparison of cells withdisclosed cathodes, with prior art cells having cathodes that lack themonomers, according to some embodiments of the invention.

FIG. 4 is an illustration of an experimental comparison of cathodeshaving pyrrole as monomer and/or oligomer material versus cathodeshaving aniline as monomer and/or oligomer material, according to someembodiments of the invention.

FIGS. 5A-5J are high resolution scanning electron microscope (HRSEM)images comparing prior art cathodes with pristine and operative cathodesrespectively, according to some embodiments of the invention.

FIG. 6 is a high level schematic illustration of a method, according tosome embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, various aspects of the present inventionare described. For purposes of explanation, specific configurations anddetails are set forth in order to provide a thorough understanding ofthe present invention. However, it will also be apparent to one skilledin the art that the present invention may be practiced without thespecific details presented herein. Furthermore, well known features mayhave been omitted or simplified in order not to obscure the presentinvention. With specific reference to the drawings, it is stressed thatthe particulars shown are by way of example and for purposes ofillustrative discussion of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

Before at least one embodiment of the invention is explained in detail,it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangement of thecomponents set forth in the following description or illustrated in thedrawings. The invention is applicable to other embodiments that may bepracticed or carried out in various ways as well as to combinations ofthe disclosed embodiments. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

It is noted that the disclosed general formulas relate to thestoichiometry of the material, which may vary by a few percent from thestoichiometry due to substitution or other defects present in thestructure.

Cathodes for a fast charging lithium ion battery, processes formanufacturing thereof and corresponding batteries are provided. Cathodeformulations comprise spinel and/or layered structure cathode material(or mixture of thereof, and possibly mixtures thereof with olivinecathode material), 5-10% of cathode material having an olivine-basedstructure as polymerization initiator, binder material, and monomerand/or oligomer material selected to polymerize into a conductivepolymer upon partial delithiation of the olivine-based structure cathodematerial during at least a first charging cycle of a cell having acathode made of the cathode formulation. When the cathode is used in abattery, polymerization is induced in-situ (in-cell) during firstcharging cycle(s) of the battery to provide a polymer matrix which isevenly dispersed throughout the cathode.

FIGS. 1 and 7 are high level schematic illustrations of cathodeformulations 100, cathodes 110, 115 and cells 120, 125, according tosome embodiments of the invention. In FIG. 1 the cathode material isbased on cathode material having an olivine-based structure, while inFIG. 7 the cathode material is based on cathode material having aspinel-based and/or layered structure, with olivine-based structurecathode material in small amount (up to 10 wt %) to initiate in-situpolymerization of the monomer and/or oligomer material, as describedbelow.

Cathode formulations 100 (see e.g., FIG. 1) may comprise cathodematerial 90 having an olivine-based structure (and optional additives,see below), binder material 98, and monomer and/or oligomer material 95selected to polymerize into a conductive polymer upon partialdelithiation of cathode material 90 during at least a first chargingcycle of cell 120, 125 having cathode 110, 115 made of cathodeformulation 100. Pristine cathode 110 and pristine cell 120 denote forexample cathodes and cells prior to their first charging cycle, whilecathode 115 and operating cell 125 denote for example cathodes and cellsafter their first charging cycle has been carried out. Dried cathodeslurries made of cathode formulations 100 are likewise part of thepresent disclosure. It is noted that similar configurations may beapplied to other electrodes and are shown here for cathodes as anon-limiting example.

Cathode formulations 100 (see e.g., FIG. 7) may comprise cathodematerial 91 having spinel-based and/or layered structure, 5-10 wt % ofcathode material 90 having an olivine-based structure (and optionaladditives, see below), binder material 98, and monomer and/or oligomermaterial 95 selected to polymerize into a conductive polymer uponpartial delithiation of olivine-based structure cathode material 90during at least a first charging cycle of cell 120, 125 having cathode110, 115 made of cathode formulation 100. Pristine cathode 110 andpristine cell 120 denote for example cathodes and cells prior to theirfirst charging cycle, while cathode 115 and operating cell 125 denotefor example cathodes and cells after their first charging cycle has beencarried out. Dried cathode slurries made of cathode formulations 100 arelikewise part of the present disclosure. It is noted that similarconfigurations may be applied to other electrodes and are shown here forcathodes as a non-limiting example.

Cathode formulations 100 in any of the embodiments may comprise(olivine-based structure) cathode material 90 consisting of A_(z)MXO₄,wherein A is Li, alone or partially replaced by at most 10% of Na and/orK; 0≤z≤1; M is at least 50% of Fe(II) or Mn(II) or mixture thereof; andXO₄ is PO₄, alone or partially replaced by at most 10 mol % of at leastone group selected from SO₄ and SiO₄. For example, cathode material 90may include LFP (LiFePO₄) cathode material. Cathode material 90 mayfurther comprise additives such as conductive materials, e.g., carbonblack and/or carbon nano-tubes. Cathode formulations 100 may comprise acarbon coating. Spinel-based and/or layered structure cathode material91 may consist of at least one of: LCO formulations (based on LiCoO₂),NMC formulations (based on lithium nickel-manganese-cobalt), NCAformulations (based on lithium nickel cobalt aluminum oxides), LMOformulations (based on LiMn₂O₄) and LMN formulations (based on lithiummanganese-nickel oxides).

In certain embodiments M may be selected from Fe(II), Mn(II) andmixtures thereof, alone or partially replaced by at most 50% of one ormore other metals selected from Ni and Co and/or by at most 15% of oneor more aliovalent or isovalent metals other than Ni or Co, and/or by atmost 5% as atoms of Fe(III).

In certain embodiments, M may be selected from Fe(II), Mn(II) andmixtures thereof, alone or partially replaced by at most 50% of one ormore other metals chosen from Ni and Co and/or by at most 15% as atomsof one or more aliovalent or isovalent metals selected from Mg, Mo, Nb,Ti, Al, Ta, Ge, La, Y, Yb, Cu, Sm, Ce, Hf, Cr, Zr, Bi, Zn, Ca, B and Wand/or by at most 5% as atoms of Fe(III).

In certain embodiments, cathode material 90 may comprise a compoundcorresponding to the general formula Li_(z)Fe_(y)Mn_(1-y)PO₄ which hasan olivine structure, wherein z and y are each independently between 0and 1 (e.g., A may be Li, M may be Fe_(y)Mn_(1-y), X may be P, 0≤z≤1,0≤y≤1, independently).

Cathode formulations 100 may comprise monomer and/or oligomer material95 consisting of monomers of any of pyrrole, aniline, thiophene, phenylmercaptan, furan, and phenol. In certain embodiments, monomer and/oroligomer material 95 may comprise oligomers, at least as part of monomerand/or oligomer material 95. In certain embodiments, monomer and/oroligomer material 95 may consist of oligomers. In certain embodiments,monomer and/or oligomer material 95 may consist of monomers. In certainembodiments, monomer and/or oligomer material 95 may compriseethylenedioxythiophene and styrenesulfonate which may polymerize toconductive polymer PEDOT-PSS(Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) upon partialdelithiation of cathode material 90 during at least a first chargingcycle of cell 120, 125. In certain embodiments, monomer and/or oligomermaterial 95 may comprise combinations of monomers and/or oligomers. Incertain embodiments, the rings in any of the monomer embodiments may besubstituted with one or more straight, branched or bridged alkyl,alkenyl, oxa-alkyl, oxa-alkenyl, aza-alkyl, aza-alkenyl, thia-alkyl,thia-alkenyl, sila-alkyl, sila-alkenyl, aryl, aryl-alkyl, alkyl-aryl,alkenyl-aryl, dialkylamino and dialkylazo compounds comprising about1-30 carbon atoms.

Cathode formulations 100 may comprise binder material 98 such ascarboxymethyl cellulose (CMC), polyvinylidene difluoride (PVDF),polyacrylic acid (PAA), polyethylene oxide (PEO), polyvinyl alcohol(PVA) and/or alginate as non-limiting examples.

Some embodiments comprise cathode formulations 100 having 80-90% ofcathode material 90, 1-10% of binder material 98 and 1-10% of monomerand/or oligomer material 95. Some embodiments comprise cathodeformulations 100 having 90-98% of cathode material 90, 1-5% of bindermaterial 98 and 1-5% of monomer and/or oligomer material 95. In certainembodiments, cathode formulations 100 may comprise more than 90% ofcathode material 90. In certain embodiments, cathode formulations 100may comprise more than 10% of binder material 98. In certainembodiments, cathode formulations 100 may comprise more than 10% ofmonomer and/or oligomer material 95. Some embodiments comprise anysub-range of weight % combinations within the disclosed ranges.

Some embodiments comprise cathode formulations 100 having 70-90% ofcathode material 91, 5-10% of olivine-based structure cathode material90, 1-10% of binder material 98 and 1-10% of monomer and/or oligomermaterial 95. Some embodiments comprise cathode formulations 100 having90-98% of cathode material 90, 1-5% of binder material 98 and 1-5% ofmonomer and/or oligomer material 95. In certain embodiments, cathodeformulations 100 may comprise between 85%-93% of cathode material 91 and5% of olivine-based structure cathode material 90. In certainembodiments, cathode formulations 100 may comprise more than 10% ofbinder material 98. In certain embodiments, cathode formulations 100 maycomprise more than 10% of monomer and/or oligomer material 95. Someembodiments comprise any sub-range of weight % combinations within thedisclosed ranges.

Cells 120, 125 may comprise cathodes 110, 115 prepared from cathodeformulations 100, as well as an anode, electrolyte and a separator(illustrated collective and schematically by a member 80 in the cell).Pristine cathode 110 is prepared from cathode formulations 100, e.g., byspreading and drying, with cathode material 90 having an olivine-basedstructure, binder material 98, and monomer and/or oligomer material 95,while cathode 115 has a conductive polymer formed during at least afirst charging cycle of cell 120, 125 from monomer and/or oligomermaterial 95. Without being bound by theory, it is suggested that thepolymerization of monomer and/or oligomer material 95 into theconductive polymer is carried out upon partial delithiation of cathodematerial 90 during the first cycle(s) of charging and discharging cell120, 125. As the polymerization probably occurs during first chargingcycle(s), it is referred to herein as in-situ, or in-cellpolymerization, in contrast to prior art cathodes which are polymerizedbefore being incorporated in operating cell 125.

In cathodes according to some embodiments of the invention, the monomerand/or oligomer material may be either in monomer and/or oligomer formor at least partially polymerized depending on whether a first chargingcycle of the cell has taken place. The monomer and/or oligomer materialmay be in monomer and/or oligomer form in the cathode in its pristineform prior to the first charging cycle of the cell, the partialdelithiation may be carried out electrochemically during the firstcharging cycle of the cell, and, following the first charging cycle ofthe cell, the monomer and/or oligomer material may be at least partlypolymerized.

Without being bound by theory, an indication to the occurrence of thepolymerization process during the charging process is illustratedschematically by peak 113 in FIGS. 1 and 7, and is further illustratedin examples provided in FIGS. 2A-2C. FIGS. 2A-2C illustrate examples fora prior art charging curve 85 (FIG. 2A), a first cycle of a chargingcurve 130 of pristine cell 120 with pristine cathode 110 having pyrrolemonomers as monomer and/or oligomer material 95 (FIG. 2B) and apotential curve 130A of pristine cathode 110 having pyrrole monomers asmonomer and/or oligomer material 95 which is surface electro-polymerizedoutside cell 120 (FIG. 2C), as comparison, according to some embodimentsof the invention. While in prior art charging 85 the measured cathodepotential is monotonous after the initial rise, charging curve 130 showsa clear local peak 113 in the potential at around 3.465V which isunderstood as corresponding to the polymerization of monomer and/oroligomer material 95 in cathode 110 in cell 120 during actual charging,once sufficient partial delithiated cathode material has formed duringthe charging, as indicated by the potential value. This understandingwas corroborated by identifying a peak 113A at a similar potential valueunder surface polymerization of pyrrole monomers on another cathode 110outside cell 120. The inventors suggest that, without being bound bytheory, local peak 113 in charging curve 130 indicates the specifiedpotential which corresponds to a polymerization reaction of monomerand/or oligomer material 95 in presence of the partially delithiatedcathode material (e.g., by oxidation). It is noted that peak 113 isreduced and/or vanishes in later cycles, probably due to the completionof the polymerization. In different experiments, local peak 113 wasfound between 3.455V-3.465V. It is noted that cathodes 115 may be madeoperable by polymerization of monomer and/or oligomer material 95 duringthe first cycle(s) even if local peak 113 is not visible on the chargingcurve, possibly due to cycling conditions and cathode composition. Thepresence of peak 113 is merely understood as a non-limiting indicator ofthe polymerization process, and not as a required condition thereto.

FIG. 3 is an illustration of an experimental comparison of cells 125with disclosed cathode 115 with prior art cells having cathodes thatlack the monomers, according to some embodiments of the invention. Thecell capacity and cyclability are exemplified at charging/dischargingrates of 0.1C, 1C, 5C, 10C and 15C, illustrating the superior capacityof cells 125, particularly at high charging rates such as 15C in whichcells 125 achieved more than threefold the capacity of prior art cells(indicated by A in the figure).

FIG. 4 is an illustration of an experimental comparison of cathodes 115having pyrrole as monomer and/or oligomer material 95 versus cathodes115 having aniline as monomer and/or oligomer material 95, according tosome embodiments of the invention. In both cases, monomer and/oroligomer material 95 was added as 5% (weight %) of the cathode slurryand both cases show high capacities in all charging rates, andparticularly at high charging rates such as 5C, 10C, 15C and possiblyhigher charging rates.

FIGS. 5A-5J are high resolution scanning electron microscope (HRSEM)images comparing prior art cathodes 86A, 86B with pristine and operativecathodes 110, 115, respectively, according to some embodiments of theinvention. FIGS. 5A and 5C show surface HRSEM images of pristine priorart cathodes 86A (LFP) and 86B (LFP with polypyrrole, polymerized priorto the first cycle, added polymerized into the cathode slurry),respectively, and FIG. 5B is a surface HRSEM image of pristine cathode110 (in the illustrated non-limiting example, LFP with pyrrole monomermaterial 95). FIGS. 5D and 5F show cross section HRSEM images ofpristine prior art cathodes 86A and 86B, respectively, and FIG. 5E is across section HRSEM image of pristine cathode 110. FIGS. 5G and 5I showsurface HRSEM images of operative cathode 115 and prior art cathode 86B,respectively. FIGS. 5H and 5J show cross section HRSEM of operativecathode 115 and prior art cathode 86B, respectively. Advantageously, theinventors have found out that the disclosed in-cell polymerization ofmonomer and/or oligomer material 95 yields thick and uniformpolymerization of polypyrrole through the whole cross section ofelectrode 115 (FIG. 5H), in stark contrast to prior art electrode 86B(FIG. 5J).

FIG. 6 is a high level schematic illustration of a method 200, accordingto some embodiments of the invention. The method stages may be carriedout with respect to cathode formulations 100, cathodes 110, 115 andcells 120, 125 described above, which may optionally be configured toimplement method 200. Method 200 may comprise stages for producing,preparing and/or using device cathode formulations 100, cathodes 110,115 and cells 120, 125 described above, such as any of the followingstages, irrespective of their order.

Method 200 may comprise configuring an olivine-based cathode for in-situ(in-cell) polymerization (stage 210), e.g., by selecting monomers whichpolymerize into a conducting polymer in presence of partiallydelithiated olivine-based cathode material (stage 215), adding themonomers to the cathode material (stage 220) configuring the cathode toundergo the polymerization during the first charging cycle(s) (stage225), e.g., polymerizing the monomers during the first charging cycle(s)(stage 230) and producing the operative cathode in-situ by thepolymerization (stage 240).

In certain embodiments, method 100 may further comprise adding up to 10%olivine-based structure cathode material to cathode material havingspinel and/or layered structure (stage 205). In certain embodiments,cathode(s) 87 may comprise materials based on layered, spinel and/orolivine frameworks, and with up to 10 wt % of LFP formulations (based onLiFePO₄) with Fe possibly partly replaced by Mn as disclosed above and90 wt % or more of any of various spinel and/or layered structurecompositions, such as LCO formulations (based on LiCoO₂), NMCformulations (based on lithium nickel-manganese-cobalt), NCAformulations (based on lithium nickel cobalt aluminum oxides), LMOformulations (based on LiMn₂O₄), LMN formulations (based on lithiummanganese-nickel oxides), lithium rich cathodes, and/or combinationsthereof.

In certain embodiments, cathode material 90 consists of A_(z)MXO₄,wherein A is Li, alone or partially replaced by at most 10% of Na and/orK; 0≤z≤1, M may be selected from Fe(II), Mn(II) and mixtures thereof,alone or partially replaced by at most 50% of one or more other metalsselected from Ni and Co and/or by at most 15% of one or more aliovalentor isovalent metals other than Ni or Co, and/or by at most 5% as atomsof Fe(III) and XO₄ is PO₄, alone or partially replaced by at most 10 mol% of at least one group selected from SO₄ and SiO₄.

In certain embodiments, M may be selected from Fe(II), Mn(II) andmixtures thereof, alone or partially replaced by at most 50% of one ormore other metals chosen from Ni and Co and/or by at most 15% as atomsof one or more aliovalent or isovalent metals selected from Mg, Mo, Nb,Ti, Al, Ta, Ge, La, Y, Yb, Cu, Sm, Ce, Hf, Cr, Zr, Bi, Zn, Ca, B and Wand/or by at most 5% as atoms of Fe(III).

In certain embodiments, cathode material 90 may comprise a compoundcorresponding to the general formula Li_(z)Fe_(y)Mn_(1-y)PO₄ which hasan olivine structure, wherein z and y are each independently between 0and 1 (e.g., A may be Li, M may be Fe_(y)Mn_(1-y), X may be P, 0≤z≤1,0≤y≤1, independently).

In certain embodiments, cathode material 90 may comprise a compoundcorresponding to the general formula Li_(z)FePO₄ which has an olivinestructure, wherein 0≤z≤1 (e.g., with M as Fe).

In certain embodiments, cathode material 90 may be a partiallydelithiated polymerization initiator with the formula C-A_(z)MXO₄,having on at least a portion of a surface thereof, a film of carbon(e.g., deposited by pyrolysis, as an additive to cathode material 90,coated on the surface, etc.). The film of carbon may be uniform,adherent and non-powdery. The film of carbon may be up to 15% of aweight of the polymerization initiator, or between 0.5%-5% of a weightof the polymerization initiator.

According to some embodiments, when the cathode is used in a batterycomprising a current collector, a first charging cycle of the cathodecauses polymerization initiator molecules (e.g., the partiallydelithiated A_(z)MXO₄) to induce polymerization of monomer and/oroligomer material 95 incorporated in cathode 110, thereby providing apolymer matrix between cathode material 90 and the current collector(not shown) to which cathode 110 is attached. According to someembodiments, the polymerization process which occurs within the cathodemay provide a polymer that is evenly dispersed throughout the cathode.

Introduction of electrochemically-active conducting polymers such aspolypyrrole (PPy) and polyaniline (PAni) into LFP/C-LFP compositecathodes is known to enhance both the capacity and rate capability. Theconductive polymers appear to provide good electronic contact betweenactive particles themselves and with the current collector, and acts asa host material for Li⁺ insertion/extraction. It has also been shownthat the Li⁺ diffusivity is greatly enhanced probably due toelectrostatic attraction between the anions of the conducting polymerand Li⁺ which can help Li⁺ pull out of LFP particles. However, in theprior art, solutions concerning the incorporation of the conductivepolymer are insufficiently effective or are industrially inapplicable.For example, prior art methods for preparing such composite cathodesinclude: (i) oxidative polymerization of the monomer in solutioncontaining suspended oxide powders, wherein the prepared PPy-LFPparticles are mixed with a binder and carbon to prepare the cathode;(ii) conventional fabrication by mixing the formerly synthesized polymerwith oxide and the inactive additives (carbon and binder). The polymercan be synthesized chemically or electrochemically using the monomeras-is or following chemical modification for covalently attaching aredox couple, such as ferrocene; (iii) in-situ electrodeposition ontodesignated current collector (e.g., stainless-steel mesh) fromsuspension containing oxide particles and a monomer in an organicsolvent (e.g., acetonitrile) via cyclic voltammetry—the resulted cathodemay be used as-is without any additional binder or additives; (iv)in-battery electro-polymerization an LFP cathode is closed in acoin-cell in the presence of a monomer dissolved in an electrolyte andthe polymer is polymerized by either a single step of charging to inducede-lithiation of the cathode or by initial charge to inducede-lithiation followed by the addition of a monomer solution after whichan additional galvanostatic step is performed to complete thepolymerization, wherein the partially delithiated lithium metalphosphate acts as a polymerization initiator.

Advantageously, while prior art polymerization is carried out prior tothe preparation of the cathode or prior to the insertion of the cathodeinto the cell, and typically from compound in the electrolyte or in asolution, disclosed cathodes 110 are prepared from slurries whichinclude monomer and/or oligomer material 95 and polymerization iscarried out in cell 120, 125 without need for separate polymerization ofmonomer and/or oligomer material 95 during the preparation of cathode110, before introducing cathode 100 into cell 120. The disclosedinvention thus provides significant process advantages as well assuperior cathodes and cells, as explained above.

In certain embodiments, the cathode may be made by preparing anelectrode slurry composition by dispersing the electrode activematerial, a binder, a conductive material and a thickener, if desired,in a solvent and coating the slurry composition on an electrodecollector. As non-limiting examples, aluminum or aluminum alloy may beused as a current collector. The current collector may be formed as afoil or mesh. In any of the disclosed embodiments, anodes may compriseanode active material particles such as graphite, graphene or othercarbon-based materials, any of a range of metalloids such as silicon,germanium and/or tin, and/or of aluminum, alloys such as lithiumtitanate and/or possibly composite core-shell particles—having differentsizes (e.g., in the order of magnitude of 100 nm, e.g., 100-500 nm,and/or possible in the order of magnitude of 10 nm or 1μ)—for receivinglithiated lithium during charging and releasing lithium ions duringdischarging. The anodes may further comprise binder(s) and additive(s)as well as optionally coatings (e.g., conductive polymers with orwithout lithium, conductive fibers such as CNTs (carbon nanotubes) orcarbon fibers). Active material particles may be pre-coated by one ormore coatings (e.g., by conductive polymers, lithium polymers, etc.),have borate and/or phosphate salt(s) bond to their surface (possiblyforming e.g., B₂O₃, P₂O₅), bonding molecules which may interact with theelectrolyte and/or various nanoparticles (e.g., boron carbide B₄C,tungsten carbide WC, vanadium carbide, titanium nitride TiN), formingmodified anode active material particles, may be attached thereto inanode preparation processes such as ball milling (see, e.g., U.S. Pat.No. 9,406,927, which is incorporated herein by reference in itsentirety), slurry formation, spreading of the slurry and drying thespread slurry. Electrolytes may comprise non-aqueous solvents such asmixtures of linear and cyclic carbonate-based solvents and one or morelithium salts, as well as additives. The non-aqueous organic solvent maycomprise any of: ester-based solvent(s), ether-based solvent(s),ketone-based solvent(s), alcohol-based solvent(s), and/or aproticsolvent(s), in addition to carbonate-based solvent(s). The lithium saltsmay be dissolved in the organic solvent(s) and be selected to performany of the following functions within the battery cells: supply lithiumions in a battery, enable operation of the rechargeable lithium battery,and improve lithium ion transportation between the positive and negativeelectrodes. Non-limiting examples for lithium electrolyte salt(s)(expressed as Li⁺X⁻in the electrolyte) may comprise, as respectiveanions X⁻, any of: F⁻, Cl⁻, Br⁻, I⁻, NO3⁻, N(CN)₂ ⁻, BF₄ ⁻, ClO₄ ⁻, PF₆⁻, (CF₃)₂PF₄ ⁻, (CF₃)₃PF₃ ⁻, (CF₃)₄PF₂ ⁻, (CF₃)₅PF⁻, (CF₃)₆P⁻, CF₃SO₃ ⁻,CF₃CF₂SO₃ ⁻, (CF₃SO₂)₂N⁻, (FSO₂)₂N⁻, CF₃CF₂ (CF₃)₂CO⁻, and combinationsthereof. The lithium salt(s) may be included in the electrolyte in aconcentration of between about 0.1 M to about 2.0 M. The concentrationrange and values may be selected to optimize the performance and thelithium ion mobility with respect electrolyte conductivity andviscosity. Various additive(s) and their combinations may be added tothe electrolyte, such as solid electrolyte interphase (SEI) formingadditives, compounds that promote high temperature stability and HFscavengers which prevent battery capacity deterioration. Separator(s)may comprise various materials, such as polyethylene (PE), polypropylene(PP) or other appropriate materials. As non-limiting examples, a polymermembrane such as a polyolefin, polypropylene, or polyethylene membrane,a multi-membrane thereof, a micro-porous film, or a woven or non-wovenfabric may be used as the separator.

In the above description, an embodiment is an example or implementationof the invention. The various appearances of “one embodiment”, “anembodiment”, “certain embodiments” or “some embodiments” do notnecessarily all refer to the same embodiments. Although various featuresof the invention may be described in the context of a single embodiment,the features may also be provided separately or in any suitablecombination. Conversely, although the invention may be described hereinin the context of separate embodiments for clarity, the invention mayalso be implemented in a single embodiment. Certain embodiments of theinvention may include features from different embodiments disclosedabove, and certain embodiments may incorporate elements from otherembodiments disclosed above. The disclosure of elements of the inventionin the context of a specific embodiment is not to be taken as limitingtheir use in the specific embodiment alone. Furthermore, it is to beunderstood that the invention can be carried out or practiced in variousways and that the invention can be implemented in certain embodimentsother than the ones outlined in the description above.

The invention is not limited to those diagrams or to the correspondingdescriptions. For example, flow need not move through each illustratedbox or state, or in exactly the same order as illustrated and described.Meanings of technical and scientific terms used herein are to becommonly understood as by one of ordinary skill in the art to which theinvention belongs, unless otherwise defined. While the invention hasbeen described with respect to a limited number of embodiments, theseshould not be construed as limitations on the scope of the invention,but rather as exemplifications of some of the preferred embodiments.Other possible variations, modifications, and applications are alsowithin the scope of the invention. Accordingly, the scope of theinvention should not be limited by what has thus far been described, butby the appended claims and their legal equivalents.

1. A cathode, prepared from a cathode formulation comprising: cathode material having spinel or layered structure, up to 10 wt % cathode material having an olivine-based structure, binder material, and monomer and/or oligomer material selected to polymerize into a conductive polymer upon partial delithiation of the olivine-based structure cathode material during at least a first charging cycle of a cell having the cathode, wherein: the monomer and/or oligomer material is in monomer and/or oligomer form in the cathode in its pristine form prior to the first charging cycle of the cell, the partial delithiation is carried out electrochemically during the first charging cycle of the cell, and following the first charging cycle of the cell, the monomer and/or oligomer material is at least partly polymerized.
 2. The cathode of claim 1, wherein the cathode material consists of at least one of: LCO formulations (based on LiCoO₂), NMC formulations (based on lithium nickel-manganese-cobalt), NCA formulations (based on lithium nickel cobalt aluminum oxides), LMO formulations (based on LiMn₂O₄) and LMN formulations (based on lithium manganese-nickel oxides).
 3. The cathode of claim 1, wherein the olivine-based structure cathode material comprises LFP (LiFePO₄).
 4. The cathode of claim 1, wherein the olivine-based structure cathode material is A_(z)MXO₄ wherein A is Li, alone or partially replaced by at most 10% of Na and/or K; 0≤z≤1, M is at least 50% of Fe(II) or Mn(II) or mixture thereof; and XO₄ is PO₄, alone or partially replaced by at most 10 mol % of at least one group selected from SO₄ and SiO₄.
 5. The cathode of claim 1, wherein the cathode material further comprises a carbon coating.
 6. The cathode of claim 1, wherein the monomer and/or oligomer material comprises monomers of at least one of pyrrole, aniline, thiophene, phenyl mercaptan, furan, phenol, ethylenedioxythiophene, styrenesulfonate and oligomers thereof.
 7. The cathode of claim 6, wherein at least one ring in the monomers is substituted with one or more straight, branched or bridged alkyl, alkenyl, oxa-alkyl, oxa-alkenyl, aza-alkyl, aza-alkenyl, thia-alkyl, thia-alkenyl, sila-alkyl, sila-alkenyl, aryl, aryl-alkyl, alkyl-aryl, alkenyl-aryl, dialkylamino or dialkylazo group, comprising 1-30 carbon atoms.
 8. The cathode of claim 1, wherein the monomer and/or oligomer material comprises a combination of monomers and oligomers.
 9. The cathode of claim 1, wherein the binder material comprises at least one of: carboxymethyl cellulose (CMC), polyvinylidene difluoride (PVDF), polyacrylic acid (PAA), polyethylene oxide (PEO), polyvinyl alcohol (PVA) and alginate.
 10. The cathode of claim 1, comprising 70-90% of the spinel or layered structure cathode material, 5-10% of the olivine-based structure cathode material, 1-10% of the binder material and 1-10% of the monomer and/or oligomer material.
 11. The cathode of claim 1, comprising 85-93% of the cathode material, 5% of the olivine-based structure cathode material, 1-5% of the binder material and 1-5% of the monomer and/or oligomer material.
 12. A cell comprising the cathode of claim
 1. 13. A cell comprising: an anode, electrolyte, a separator, and a cathode comprising: cathode material having spinel or layered structure, up to 10 wt % cathode material having an olivine-based structure, binder material, and a conductive polymer formed during at least a first charging cycle of the cell from monomer and/or oligomer material selected to polymerize into the conductive polymer upon partial delithiation of the cathode material, wherein: the monomer and/or oligomer material is in monomer and/or oligomer form in the cathode in its pristine form prior to the first charging cycle of the cell, the partial delithiation is carried out electrochemically during the first charging cycle of the cell, and following the first charging cycle of the cell, the monomer and/or oligomer material is at least partly polymerized.
 14. The cell of claim 13, wherein the cathode material consists of at least one of: LCO formulations (based on LiCoO₂), NMC formulations (based on lithium nickel-manganese-cobalt), NCA formulations (based on lithium nickel cobalt aluminum oxides), LMO formulations (based on LiMn₂O₄) and LMN formulations (based on lithium manganese-nickel oxides).
 15. The cell of claim 13, having a charging curve, in at least a first charging thereof, which comprises a local peak at a specified potential which corresponds to a polymerization reaction of the monomer and/or oligomer material in presence of the partially delithiated olivine-based structure cathode material.
 16. A method comprising configuring, for in-situ polymerization, a cathode made of cathode material having spinel or layered structure, by adding to the cathode material up to 10 wt % cathode material having an olivine-based structure and monomer and/or oligomer material selected to polymerize into a conductive polymer upon partial delithiation of the olivine-based structure cathode material during at least a first charging cycle of a cell with the cathode, wherein the monomer and/or oligomer material is in monomer and/or oligomer form in the cathode in its pristine form prior to the first charging cycle of the cell, the partial delithiation is carried out electrochemically during the first charging cycle of the cell, and following the first charging cycle of the cell, the monomer and/or oligomer material is at least partly polymerized.
 17. The method of claim 16, further comprising polymerizing the monomer and/or oligomer material during the at least first charging cycle of the cell.
 18. The method of claim 16, wherein the monomer and/or oligomer material comprises monomers and oligomers, and the method further comprises polymerizing the monomers and the oligomers during the at least first charging cycle of the cell.
 19. The method of claim 16, further comprising operating the cell at a charging and/or discharging rate of at least 5C.
 20. The method of claim 16, wherein the cathode material having spinel or layered structure consists of at least one of: LCO formulations (based on LiCoO₂), NMC formulations (based on lithium nickel-manganese-cobalt), NCA formulations (based on lithium nickel cobalt aluminum oxides), LMO formulations (based on LiMn₂O₄) and LMN formulations (based on lithium manganese-nickel oxides). 